The diagnosis of gastrointestinal tuberculosis (GITB) is often delayed, increasing the morbidity associated with this treatable condition. In this case series, the clinical presentations and outcomes of 18 patients with GITB are reviewed. Our aim was to elucidate the presenting signs and symptoms of GITB so as to help physicians improve their ability to make this diagnosis. Cases were gathered retrospectively over an 8-year period from Santa Clara Valley Medical Center, San Jose, California. Sources of information included patient records from our TB clinic and our hospital from 1989 to 1997. Of the 18 patients, 16 had a definitive diagnosis of GITB made from histology and/or culture from an abdominal source. In the remaining two patients, a presumptive diagnosis of GITB was made based on the co-occurrence of abdominal signs and symptoms, response to antituberculous therapy, and Mycobacterium tuberculosis identified at a nonabdominal site. The most common clinical presentation was a triad of abdominal pain, fever, and weight loss. This triad was present in 8 of 18 patients. Seven patients presented with two of these signs and symptoms, two had abdominal pain alone, and one presented with other symptomatology. Time to diagnosis ranged from 2 days to 11 months, with a mean time to diagnosis of 50 days. These findings suggest that the diagnosis of GI and hepatic TB is often delayed. Possible reasons for delay include nonspecific signs and symptoms and failure to consider TB in the initial differential diagnosis. Once diagnosed, the outcome of GITB in this series was favorable.